采用平衡合金法,利用X射线衍射、扫描电镜及能谱分析,系统地研究了Mg-Zn-Al三元系富镁角335°C的平衡相组成及其成分。从实验上证实,α-Mg固溶体并不与Mg32(Al,Zn)49(τ)三元金属间化合物或q准晶相平衡,而仅与一个三元化合物Al5Mg11Zn4(φ)相平衡。获得了φ相在335°C的整个成分范围,即:52.5%~56.4%Mg、13.6%~24.0%Al、19.6%~33.9%Zn(摩尔分数)。Al在Mg Zn相中的固溶度远大于在Mg7Zn3相中的固溶度,其最大值可达8.6%Al(摩尔分数)。Al和Zn可以同时固溶在α-Mg固溶体中。
The phase equilibria and compositions at the Mg-rich corner of the Mg?Zn?Al ternary system at 335 °C were systemically investigated through the equilibrated alloy method by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) assisted with energy dispersive spectroscopy of X-ray (EDS). It is experimentally testified that theα-Mg solid solution is not in equilibrium with the Mg32(Al, Zn)49 (τ) ternary intermetallic compound orq quasicrystalline phase, but only in equilibrium with one ternary intermetallic compound Al5Mg11Zn4 (φ). The whole composition range of theφ phase was also obtained at 335 °C, i.e., 52.5%?56.4% Mg, 13.6%?24.0% Al, 19.6%?33.9% Zn (mole fraction). The solubility of Al in the MgZn phase is remarkably more than that in the Mg7Zn3 phase, and the maximum is about 8.6% Al. Aluminum and zinc are simultaneously soluble in theα-Mg solid solution.